|
| |
TM 9-2320-360-20-1
2-13. INTRODUCTION TO LOGIC TREE TROUBLESHOOTING (CONT)
e.
Abbreviations And Commonly Used Terms
(1)
A/D - Analog to Digital: The computer inside the ECM uses an A/D converter to convert a sensor voltage
into a number with which the computer can work.
(2)
Active Codes - These are the codes that currently keep the CHECK ENGINE indicator on. They are read
using the Diagnostic Data Reader.
(3)
BAT - Battery
(4)
CEL - CHECK ENGINE indicator: mounted on the instrument dash and used as panel. It has two
functions:
(a)
a warning lamp to tell the driver that a problem has occurred, and that the vehicle should be taken in
for service as soon as possible.
(b)
as a light bulb check and system check the CHECK ENGINE indicator will come on for about five
seconds when the ENGINE switch is turned ON. If the CEL remains on, the self-diagnostic system
has detected a problem. If the problem goes away, the light will go out, but the (HISTORICAL)
trouble code will be stored in the ECM. (See General Diagnostic Information)
(5)
CKT - Circuit
(6)
CLS - Coolant Level Sensor: Monitors coolant level at the radiator tank top.
(7)
COM - Common 3
(8)
CTS - CONTACT TEST SET: Tool used for troubleshooting DDEC and for STE/ICE-R tests.
(9)
DCA - Diagnostic Connector Assembly: An electrical harness on the vehicle which allows the STE/ICE-R to
be powered and to make measurements of key vehicle signals from a single connection. In addition to
many basic electrical signals such as starter voltage and current, it includes engine speed and fuel supply
pressure. The STE/ICE-R can make TK measurements at the same time that it is connected to the DCA.
(10)
DDEC - Second generation Engine Electronic Controls
(11)
DDL - Diagnostic Data Link: The lines (wires) over which the ECM communicates information to be read by
a Diagnostic Data Reader.
(12)
Diagnostics: Troubleshooting by following an exact procedure.
(13)
DL+ - Data Link, positive side. Used for communications to the Diagnostic Data Reader, as well as other
applications.
(14)
DL - Data Link, negative side (See above).
(15)
DREQ - Diagnostic Request Terminal: The pin on the DDL connector which must be grounded to obtain
diagnostic codes (pin M).
(16)
ECM - Electronic Control Module: The brains of DDEC. It reads the DDEC sensors and switches,
calculates injector firing times and duration (using a built-in computer), and fires the injectors at the
appropriate times.
(17)
EEPROM - Electronically Erasable Programmable Read Only Memory. Contains the engine calibration.
(18)
EFPA - Electronic Food Pedal Assembly: contains the Throttle Positions Sensor
(19)
Erratic: intermittent
(20)
EUI - Electronic Unit Injector: replaces the Mechanical Unit Injector (MUI)
2-74 Change 2
|
